Probe apparatus with optical length-measuring unit and probe testing method

Abstract

A probe apparatus with control-position detection means is provided for testing an electrical characteristic of a to-be-tested object formed on a substrate W. The probe apparatus includes a prober chamber, a susceptor provided in the prober chamber for placing thereon a to-be-tested object, and a moving mechanism for moving the susceptor in X-, Y-, Z- and θ-directions. The probe apparatus further includes a probe card having a plurality of probes and opposing the susceptor, and a first optical length-measuring unit. The first length-measuring unit emits light to the surface of the to-be-tested object placed on the susceptor, and detects the Z-directional position of the to-be-tested object based on the light reflected from the object. The probe apparatus can have a second length-measuring unit.

What is claimed is: 
     
       1. A probe apparatus for testing an electrical characteristic of a to-be-tested object formed on a substrate W, comprising:
 a prober chamber; 
 a susceptor provided in the prober chamber and configured to place thereon a substrate with a plurality of to-be-tested objects formed; 
 a probe card provided in the prober chamber, the probe card including a plurality of probes and opposing the susceptor; and 
 a first optical length-measuring unit configured to emit light to a surface of at least one to-be-tested object placed on the susceptor, detect a position, on a light-receiving surface of the first optical length-measuring unit, of light reflected from said at least one to-be-tested object, and detect a Z-directional position of said at least one to-be-tested object based on the detected position of light reflected. 
 
     
     
       2. The probe apparatus according to  claim 1 , further comprising a reference plane attached to the susceptor, the reference plane being referred to when the first optical length-measuring unit detects the Z-directional position. 
     
     
       3. The probe apparatus according to  claim 1 , wherein the light emitted from the first optical length-measuring unit is a laser beam. 
     
     
       4. The probe apparatus according to  claim 3 , wherein the laser beam has a diameter of 10 to 30 μm. 
     
     
       5. The probe apparatus according to  claim 1 , wherein the first optical length-measuring unit is attached to one of an upper wall and a sidewall of the prober chamber. 
     
     
       6. The probe apparatus according to  claim 1 , further comprising a moving mechanism configured to move the susceptor in a Z-direction, and a control unit configured to control the moving mechanism,
 and wherein: 
 the first optical length-measuring unit detects Z-directional positions of a plurality of surface portions of one of the susceptor and the substrate placed on the susceptor; and 
 the control unit creates a map concerning the Z-directional positions of the plurality of surface portions, based on the Z-directional positions of the plurality of surface portions detected by the first optical length-measuring unit. 
 
     
     
       7. The probe apparatus according to  claim 1 , further comprising a second optical length-measuring unit configured to emit light to a surface of a support member supporting the probe card, detect a position, on a light-receiving surface of the second optical length-measuring unit, of light reflected from the support member, and detect a Z-directional position of the probe card based on the detected position of light reflected. 
     
     
       8. The probe apparatus according to  claim 7 , wherein the light emitted from the second optical length-measuring unit is a laser beam. 
     
     
       9. The probe apparatus according to  claim 7 , further comprising a holding plate located above the probe card, and wherein the second optical length-measuring unit is attached to a surface of the holding plate opposing the probe card. 
     
     
       10. The probe apparatus according to  claim 9 , further comprising a probe-card support member supporting the probe card, the probe-card support member being attached to an upper surface of the probe card, and wherein the second optical length-measuring unit detects an upper surface of the probe-card support member to detect a change in the Z-directional position of the probe card. 
     
     
       11. The probe apparatus according to  claim 10 , wherein the probe-card support member includes a reflector provided on a portion thereof to be detected by the second optical length-measuring unit, the reflector reflecting the emitted light. 
     
     
       12. The probe apparatus according to  claim 7 , wherein the second optical length-measuring unit detects a side surface of the probe card to detect a change in the Z-directional position of the probe card. 
     
     
       13. The probe apparatus according to  claim 12 , wherein the probe card includes an optical element provided on a side surface thereof to be detected by the second optical length-measuring unit, the optical element reflecting the emitted light. 
     
     
       14. A method of testing a to-be-tested object using the probe apparatus as claimed in  claim 1 , comprising:
 (a) placing the substrate on the susceptor; 
 (b) (b1) detecting a Z-directional position of a reference plane attached to the susceptor, using the first optical length-measuring unit; 
 (b2) raising the susceptor and bringing the reference plane into contact with the probes to determine a distance between the reference plane and the probes; 
 (c) detecting a Z-directional position of the to-be-tested object, using the first optical length-measuring unit; 
 (d) measuring a distance between a surface of the to-be-tested object and tips of the probes based on results of said (b) and (c); 
 (e) raising the susceptor in a Z-direction to bring the to-be-tested object into contact with the probes, using a moving mechanism based on the distance between the to-be-tested object and the probes detected in said (d); and 
 (f) measuring an electrical characteristic of the to-be-tested object. 
 
     
     
       15. The method according to  claim 14 , wherein:
 said (c) includes: 
 (c1) detecting Z-directional positions of a plurality of surface portions of the substrate, using the first optical length-measuring unit; and 
 (c2) creating a map concerning the detected Z-directional positions of the plurality of surface portions of the substrate, and 
 said (d) includes moving the susceptor in the Z-direction to bring the to-be-tested object into contact with the probes, using the moving mechanism based on the map created in said (b) and (c2). 
 
     
     
       16. The method according to  claim 14 , further comprising,
 (a2) after said (a), a second optical length-measuring unit emitting light to an upper surface of a support member supporting the probe card, detecting a position, on a light-receiving surface of the second optical length-measuring unit, of light reflected from the support member, and detecting a Z-directional position of the probe card based on the detected position, 
 and wherein said (d) includes detecting a distance between the to-be-tested object and the probes, based on the detection result acquired in said (a2) in addition to the detection results acquired in said (b) and (c). 
 
     
     
       17. The method according to  claim 14 , further comprising:
 (g) after said (f), moving the substrate by a measuring pitch corresponding to one to-be-tested object, repeating said (e) to (f) to measure next to-be-tested objects.